I am travelling to view a 1986 GMC school bus 170K asking $2500, seats already removed but still needs conversion (it was posted here quite a while ago but I saw no bites so wondering why)

7.? diesel wit auto transmission

Anyone have any comments on this model to consider?

I have a good diesel mech coming with me but I plan to make this a cross USA venture next year so I'm wondering what concerns there might be.

I spoke with the seller, seems upfront about things and seen many pics it looks clean etc but if anyone has any inside knowledge in this model it would be greatly appreciated. Just trying to be careful here.

My guess is that it's a 8.2 Detroit. That came out in 1980 and certainly was the most common diesel in GM medium trucks in that era. I think it's too early to be a 3116. A 1986 8.2 should have the revisions done to the head (headbolts specifically) to make it reliable.

I don't personally own nor have I ever owned an 8.2, but everyone that has one seems to be reasonably satisfied. They have decent power in turbocharged trim I believe and they are noted for getting good mileage. They were a common engine so parts and competent mechanics shouldn't be hard to find. At the same time the engine is no longer produced so don't expect every NAPA and Carquest to have stuff on hand for it.

The transmission is most likely an Allison AT545. You can read up on the advantages and disadvantages of an AT545 versus an MT643 but suffice it to say that the tranny will be fine.

I'd look at the common stuff...rust, tires, fluid levels, driveability, top speed, service records, etc. Then offer him less than $2500 and hopefully sign the paperwork to take it home.